Just FYI. In case it helps...
DR750 was made since 1988-89, DR800 SR42 was made till end 1991, DR800 SR43 was made till end 1997.
Spare parts are available from Suzuki dealers in Europe and (I could be wrong here) Canada at least. Also quite few online shops sell parts with worldwide shipment. Also there is specialized website/shop in Germany for tuning and rallying of DR and consumables (bearings, seals etc.).
I heard also that in Latin America DRs are "supported". In US DR is rare grey import beast. Same in Africa.
Obviously DR not supported as widely as XT.
In Western Europe XTs 600 is not really that common or popular, XT-Es and XTs 660 more, but worldwide I can only guess XT family is better supplied than DR. Probably XT experts can advice if there is still difference in level of support between XT600, XT600E, XT660 etc. etc.